Echo-planar imaging of porous media with spatial resolution below 100 mu m

A modified version of the echo-planar imaging technique incorporating a Car r-Purcell train of 180 degrees rf pulses (PEPI) has been implemented on a s tandard spectrometer. It is demonstrated that artifacts in the image due to cumulative errors in the rf field can be reduced by replacing each 180 deg rees pulse by a composite sequence of three rf pulses. Artifact-free 3D ima ges at 94 mu m voxel resolution are obtained within 15 min. This technique has been applied to study the drying process in an initially water-saturate d model porous medium with characteristic T-2* of order 700 mu s. (C) 1999 Academic Press.